[WIP] Add variable pre-factors to Fourier gen.

src/gstools/field/generator.py

@@ -635,7 +635,7 @@ def __init__(
         # set model and seed
         self.update(model, seed)
 
-    def __call__(self, pos, add_nugget=True):
+    def __call__(self, pos, add_nugget=True, phase_factor=2.*np.pi, spec_factor=1., var_factor=1.,):
         """Calculate the modes for the Fourier method.
 
         This method  calls the `summate_*` Cython methods, which are the
@@ -674,10 +674,12 @@ def __call__(self, pos, add_nugget=True):
             self._z_1,
             self._z_2,
             pos,
+            phase_factor,
+            spec_factor,
         )
         nugget = self.get_nugget(summed_modes.shape) if add_nugget else 0.0
         return (
-            np.sqrt(2.0 * self.model.var / np.prod(domain_size)) * summed_modes
+            np.sqrt(var_factor * 2.0 * self.model.var / np.prod(domain_size)) * summed_modes
             + nugget
         )
 

src/gstools/field/srf.py

@@ -115,6 +115,9 @@ def __call__(
         mesh_type="unstructured",
         post_process=True,
         store=True,
+        phase_factor=2.*np.pi,
+        spec_factor=1.,
+        var_factor=1.,
     ):
         """Generate the spatial random field.
 
@@ -159,7 +162,18 @@ def __call__(
         # get isometrized positions and the resulting field-shape
         iso_pos, shape = self.pre_pos(pos, mesh_type)
         # generate the field
-        field = np.reshape(self.generator(iso_pos), shape)
+        try:
+            field = np.reshape(
+                self.generator(
+                    iso_pos,
+                    phase_factor=phase_factor,
+                    spec_factor=spec_factor,
+                    var_factor=var_factor
+                ),
+                shape,
+            )
+        except TypeError:
+            field = np.reshape(self.generator(iso_pos, ), shape)
         # upscaled variance
         if not np.isscalar(point_volumes) or not np.isclose(point_volumes, 0):
             scaled_var = self.upscaling_func(self.model, point_volumes)

src/gstools/field/summator.pyx

@@ -96,7 +96,6 @@ def summate_incompr(
                 summed_modes[d, i] += (
                     proj[d] * (z_1[j] * cos(phase) + z_2[j] * sin(phase))
                 )
-
     return np.asarray(summed_modes)
 
 
@@ -105,7 +104,9 @@ def summate_fourier(
     const double[:, :] modes,
     const double[:] z_1,
     const double[:] z_2,
-    const double[:, :] pos
+    const double[:, :] pos,
+    const double phase_factor,
+    const double spec_factor,
     ):
     cdef int i, j, d
     cdef double phase
@@ -122,7 +123,8 @@ def summate_fourier(
             for d in range(dim):
                 phase += modes[d, j] * pos[d, i]
             # OpenMP doesn't like *= after +=... seems to be a compiler specific thing
-            phase = phase * 2. * pi
-            summed_modes[i] += spectral_density_sqrt[j] * (z_1[j] * cos(phase) + z_2[j] * sin(phase))
+            # phase = phase * 2. * pi
+            phase = phase * phase_factor
+            summed_modes[i] += spec_factor * spectral_density_sqrt[j] * (z_1[j] * cos(phase) + z_2[j] * sin(phase))
 
     return np.asarray(summed_modes)